Put sugar cake decorations into a search engine. Lots of stuff comes up...
Here's one.
Linda C

Here is a link that might be useful: sugar decorations

There's a Christian assortment that should fit on an Oreo. They include a cross & are 1" to 1 1/4".

Here is a link that might be useful: Assortment

These are also about 1" & come in pink & blue. It wouldn't be hard to decorate your cookies with one of those icing tubes available now if these aren't what you want.

Here is a link that might be useful: Pink/blue crosses